Ignition device for a gas-discharge lamp

ABSTRACT

The ignition device is intended for a gas discharge lamp, i.e. arc lamp, which is immersed in a fluid medium of high dielectric constant. For ignition, the lamp supply voltage is augmented by a low-frequency ignition pulse passing through an ignition pulse coil added either to the secondary winding of the supply transformer or to a choke in the supply circuit. The highvoltage, low frequency ignition pulse is produced by a spark gap circuit, whereby the high-frequency components of the discharge voltage are filtered out by the inductance of the ignition pulse coil.

United States Patent IGNITION DEVICE FOR A GAS-DISCHARGE LAMP 11 Claims, 3 Drawing Figs.

U.S. C1 315/171, 315/112, 315/176, 315/290, 315/334 1nt.Cl 1105b 41/16, 1-105b4l/30 Field of Search 315/289,

voltage doubler rectifier SpVd FS I W1 I A. powe source r C1 Source z spark gap/ignition voltage ignition transformer [56} References Cited UNITED STATES PATENTS 3,259,796 7/1966 Hallay 315/176X 3,320,476 5/1967 Beese 315/289 Primary Examiner-John Kominski Assistant Examiner-E. R. LaRoche Attorney-Otto John Munz ABSTRACT: The ignition device is intended for a gas discharge lamp, i.e. arc lamp, which is immersed in a fluid medium of high dielectric constant. For ignition, the lamp supply voltage is augmented by a low-frequency ignition pulse passing through an ignition pulse coil added either to the secondary winding of the supply transformer or to a choke in the supply circuit. The high-voltage, low frequency ignition pulse is produced by a spark gap circuit, whereby the highfrequency components of the discharge voltage are filtered out by the inductance of the ignition pulse coil.

gplz transformer Earning volt PATENTEDHAR 2191i 3561.993

voltage doubler rectifier Fs 1 W1 Earning volt I 1 L source T I plz transformer SpVd A.C. power source z spark gap/ignition voltage ignition transformer Fig.1

SpVd

FS w Circulating means Control ignition voltage Temperature Control supply {burning voltage Fig.3 INVENTOR WA LTLIK H. STURM ATTORNEY IGNITION DEVICE FOR A GAS-DISCHARGE LAMP BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for a gas discharge lamp which is to be immersed in a liquid electrode medium having a high dielectric constant and which comprises a discharge control means in the supply circuit.

2. Description of the Prior Art Sparking devices of the prior art employ a high-voltage rectifier which rectifies the high-frequency AC supplied by a transformer. The rectified voltage charges a condenser. The condenser charge causes the ignition when it reaches the ignition voltage of the gas discharge lamp. Prior art burner devices, for example, devices submerged in water employing a highfrequency voltage pulse for ignition were not successful. The inventor discovered that such a disadvantage occurs not only in lamps submerged in water but also as a matter of principle consistently whenever the surrounding medium has a high-dielectric constant. It was found that the high-frequency voltage, by polarizing the medium, made the latter conductive for high-frequency current, thereby preventing attainment of the voltage level necessary for ignition of the gas discharge lamp.

SUMMARY OF THE INVENTION The objects of the invention are: to provide an ignition device of the character described, improved over those of the prior art, which effectively permits ignition of a gas discharge lamp in a medium of a high dielectric constant, in which it is immersed;

to accomplish firing of the discharge lamp by superimposing onto the supply burning voltage an ignition voltage pulse with strong low frequency components, such as are obtained for instance by a spark discharge;

to accomplish the object for instance by discharging a condenser over a spark-gap to produce a frequency mixture whose low-frequency components are delivered to the burner over an ignition pulse winding;

to provide for the firing of a gas discharge lamp, in a medium of a high dielectric constant without necessitating a large amount of ignition energy as compared to the energy required with the firing devices of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic representation of a preferred embodiment of the inventionemploying a transformer TRl with three windings;

FIG. 2 is a diagrammatic representation of the embodiment of the invention, shown in FIG. 1 with a substitution of a choke for the above transformer circuitry; and

FIG. 3 is a section of the circuitry common to FIGS. 1 and 2, showing the discharge lamp itself with additional means of control of the medium surrounding it.

In FIG. I is illustrated an ignition device for a gas discharge lamp (1) the lamp containing an upper and a lower electrode, an elongated body L, partially immersed in a vessel, filled with a medium F having a high-dielectric constant. The level of the medium is to reach at least the level of the upper electrode.

A circuit is provided comprising an AC power supply, an ignition transformer Tr2, having a primary winding connected to the AC power supply and a secondary winding, a doubler voltage rectifier SpVd, a charging resistor R1, a capacitor C1, a spark gap FS, a supply transformer Trl having a primary winding and a secondary winding and an ignition pulse winding WI. The ignition transformer is shown connected over the voltage doubler rectifier through the resistor to the charging capacitor, connected in spark gap F5 and the first outlet of the ignition pulse winding W1 of the supply transformer. The other leg of the capacitor is shown connected with the second terminal of the ignition pulse winding. The upper electrode of the gas discharge lamp is connected with one terminal of the second winding of the supply transformer, the lower electrode is connected with its opposite terminal.

When the ignition voltage is reached in the capacitor, sparking occurs over the spark gap. The spark gap may be a plain open spark gap or it may be for instance a glimmer tube, glow tube, klystron or equivalent.

The capacitor discharges thereby through the spark gap over the ignition pulse winding. The ignition pulse winding of the supply transformer thus delivers the necessary voltage for the firing of the gas discharge lamp. By means of the circuit shown, the burning voltage is augmented with an igniting voltage pulse, using the high-voltage low-frequency component from the spark discharge. Thus, it is possible for instance to discharge a capacitor over a spark gap producing a mixture of frequencies in a broad spectrum, the low-frequency components of which only pass to the burner circuit over the ignition pulse winding.

The invention permits firing of the gas discharge lamp in media of high dielectric constants without the necessity of a larger amount of ignition energy, as compared to the firing devices of the prior art.

The frequency mixture (broad spectrum) which occurs during ignition in the spark gap contains synchronized harmonics.

The inductance and the capacitance of the transformer provide a high-frequency filter for the upper portion of frequency spectrum, accepting only low-frequency components of the spectrum which are superimposed to the burner voltage.

The firing of the gas discharge lamp therefore occurs at a high voltage, resulting from the augmentation of the burner voltage with the low-frequency voltage components of the frequency mixture produced by the discharge in the spark gap.

In FIG. 2, another embodiment of the firing device is shown which differs from the arrangement of FIG. 1 only by the change in the burner voltage supply for the gas discharge lamp.

A resistor R2 is provided in parallel to the gas discharge lamp L, and a choke D is positioned in the anode line of the lamp L with an ignition pulse winding W1 arranged therewith. When the burner voltage is switched on (1) a small current flows over the resistor R2, permitting a buildup of a magnetic field of the choke.

As previously, ignition is produced over the spark gap Fs whereby the burner voltage is augmented by a low frequency voltage pulse from the spark gap. The firing of the gas discharge lamp occurs when the burner supply voltage and the ignition pulse voltage are combined in the same manner as described above with reference to FIG. 1.

The dielectric constant of the medium which varies widely for different substances and is well known to those skilled in the art is selected from case to case in accordance with the particular requirements on the medium as an optical filter. Moreover, the values of the dielectric constant 6 may be adjusted within limits to different conditions of temperature and pressure as expressed in the following equation:

t temperature in degrees C.

In consequence thereof the invention optionally provides for the vessel containing the dielectric medium to be closed airtight, and provided with temperature and pressure control means.

The medium may be utilized as a filter for a variety of gas discharge lamps, including mercury arc tubes, Gesiler tubes, etc. The filter may be employed to screen out for instance infrared portions of the optical spectrum, or other radiations, depending on the purpose for which the tube is to be utilized, such as for instance as a sun lamp, or for illumination and others. For such purposes other materials may be admixed to the medium to produce different desired effects, a simple example being a coloring matter. These materials may be admixed as flowable solids of microsizes, and means may be included to keep the medium agitated and the solids suspended, or solids may be selected which will dissolve or chemically react with the medium selected, for such a purpose.

it should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples chosen for the purpose of the disclosure, which do not constitute departures from the scope of the invention as claimed in the appended claims.

lclaim:

1. An ignition device for a discharge lamp immersed in a medium with a high-dielectric constant, comprising in combination:

a vessel containing a fluid medium which has a high-dielectric constant, and wherein the gas discharge lamp is immersed at least partially;

a periodic supply circuit means connected to the lamp terminals to supply thereto a burning voltage;

ignition circuit means cooperating with the supply circuit means to produce a high-voltage, low-frequency ignition pulse and to superimpose this pulse over the burning voltage on the gas discharge lamp, thereby producing the potential necessary for igniting the lamp;

the ignition circuit means including an AC-powered spark gap circuit for the creation of a series of high-voltage pulses, and means to filter out fromthese pulses any highfrequency components.

' 2. An ignition device for a gas discharge lamp as claimed in claim 1, the ignition circuit means further including, in the spark gap circuit:

a voltage doubler rectifier (SpVd);

a capacitor (C,), and a spark gap (FS) over which the capacitor discharges after reaching a predetermined voltage potential, thereby producing a mixture of high and low frequencies, the high-frequency components thereof being filtered out by the filtering means.

3. An ignition device for a gas discharge lamp as claimed in claim 2, the filtering means of the ignition circuit means including an ignition pulse winding (W connected in series with the spark gap circuitand coupled with the lamp supply circuit means so as to filter out, by its capacitance and inductance, the high-frequency components of the discharge pulse received from the spark gap, while superimposing its low-frequency components over the burning voltage supplied to the lamp over the supply circuit means.

4. An ignition device for a gas discharge lamp as claimed in claim 3, the supply circuit means including a supply transformer whose secondary winding is connected to the terminals of the lamp; the ignition pulse winding being also arranged on the secondary side of the supply transformer.

5. An ignition device for a gas discharge lamp as claimed in claim 3, the supply circuit means including a choke (D) connected to one lamp terminal and a resistor (R2) connected in parallel with the choke and the lamp so that the current flowing over this resistor allows the buildup of a magnetic field around the choke; the ignition pulse winding being arranged in the magnetic field of'the choke.

6. An ignition device for a gas discharge lamp as claimed in claim 1, said fluid medium being a gas;

7. An ignition device for a gas discharge lamp as claimed in claim 1, said fluid medium being a liquid.

8. An ignition device for a gas discharge lamp as claimed in claim 1, said fluid medium including suspended solids.

9. An ignition device for a gas discharge lamp as claimed in claim 1, and means to control the pressure of said medium.

10. An ignition device for a gas discharge lamp as claimed in claim 1, and means to control the temperature of said medi- 11. An ignition device for a gas discharge lamp as claimed in claim 1, and means to keep the medium in circulation. 

1. An ignition device for a discharge lamp immersed in a medium with a high-dielectric constant, comprising in combination: a vessel containing a fluid medium which has a high-dielectric constant, and wherein the gas discharge lamp is immersed at least partially; a periodic supply circuit means connected to the lamp terminals to supply thereto a burning voltage; ignition circuit means cooperating with the supply circuit means to produce a high-voltage, low-frequency ignition pulse and to superimpose this pulse over the burning voltage on the gas discharge lamp, thereby producing the potential necessary for igniting the lamp; the ignition circuit means including an AC-powered spark gap circuit for the creation of a series of high-voltage pulses, and means to filter out from these pulses any high-frequency components.
 2. An ignition device for a gas discharge lamp as claimed in claim 1, the ignition circuit means further including, in the spark gap circuit: a voltage doubler rectifier (SpVd); a capacitor (C1), and a spark gap (FS) over which the capacitor discharges after reaching a predetermined voltage potential, thereby producing a mixture of high and low frequencies, the high-frequency components thereof being filtered out by the filtering means.
 3. An ignition device for a gas discharge lamp as claimed in claim 2, the filtering means of the ignition circuit means including an ignition pulse winding (W1) connected in series with the spark gap circuit and coupled with the lamp supply circuit means so as to filter out, by its capacitance and inductance, the high-frequency components of the discharge pulse received from the spark gap, while superimposing its low-frequency components over the burning voltage supplied to the lamp over the supply circuit means.
 4. An ignition device for a gas discharge lamp as claimed in claim 3, the supply circuit means including a supply transformer whose secondary winding is connected to the terminals of the lamp; the ignition pulse winding being also arranged on the secondary side of the supply transformer.
 5. An ignition device for a gas discharge lamp as claimed in claim 3, the supply circuit means including a choke (D) connected to one lamp terminal and a resistor (R2) connected in parallel with the choke and the lamp so that the current flowing over this resistor allows the buildup of a magnetic field around the choke; the ignition pulse winding being arranged in the magnetic field of the choke.
 6. An ignition device for a gas discharge lamp as claimed iN claim 1, said fluid medium being a gas.
 7. An ignition device for a gas discharge lamp as claimed in claim 1, said fluid medium being a liquid.
 8. An ignition device for a gas discharge lamp as claimed in claim 1, said fluid medium including suspended solids.
 9. An ignition device for a gas discharge lamp as claimed in claim 1, and means to control the pressure of said medium.
 10. An ignition device for a gas discharge lamp as claimed in claim 1, and means to control the temperature of said medium.
 11. An ignition device for a gas discharge lamp as claimed in claim 1, and means to keep the medium in circulation. 